1997 Cadillac DeVille Owner's Manual - Page 265

NOTICE: In cold weather, water canfreeze and crack the engine, radiator, heater core and other parts. So use the recommended coolant. I You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and itwill burn if the engineparts are hot enough. Don't spill coolant on hot engine. a 1. You can remove the coolant surge tank pressure cap when the cooling system, including the coolant surge tank pressure cap and upper radiator hose, is no longer hot. Turn the pressure cap slowly counterclockwise until it first stops. (Don't press down while turning the pressure cap.) If you hear a hiss, waitfor that toston A hiss means there is still some pressure left. 5-22